Axial flow fan arrangement for fan coil unit



Oct. l, 1968v I R. G: MINER 3,403,725

AXIAL FLOW FAN ARRANGEMENT FOR FAN COIL UNIT Filed Oct. 4, 1966 2 Sheets-Sheet l FIG.2

NVENTOR. ROBERT G. MINER BY z/ z www ATTORNEY R. G. MINER 3,403,725

AXIAL FLOW FAN ARRANGEMENT FOR FAN COIL UNITV Oct. l, 1968 2 Sheets-Sheet Filed Oct. '4, 1966 A\'\'E.\'TOR, ROBERT G. MINER ATTORNEY United States Patent v`O 3,403,725 AXIAL FLOW FAN ARRANGEMENT FOR FAN COIL UNIT Robert G. Miner, La Crosse, Wis., .assignor to The Trane Company, La Crosse, Wis., a corporation of Wisconsin .Filed Oct. 4, 1966, Ser. No. 584,198 3 Claims. 4,(Cl. 165-122) ABSTRACT F THE DISCLOSURE This invention relates to air conditioning units of the type comprising a fan and heat exchange coil positioned within a casing. The casing is normally provided with inlet and outlet openings through which air from a conditioned space, as well as fresh airin some instances, may be circulated over the coil. Individual units of this type .are installed in rooms to be conditioned, and are commonly referred to as unit ventilators.

The installation of such units along room walls necessarily results in the utilization of space which could normally be beneficially employed for other purposes. Therefore, a major portion of the design work in this field has been directed towards reducing the size of fancoil units to the Iabsolute minimum consistent with satis- .factory engineering performance.

vThe current, substantially universal use of centrifugal fans in fan-coil cabinets has limited the extent to which the depth of the cabinet can be reduced. An example of the installation of centrifugal fans within a unit ventilator cabinet is shown in U.S. Patent No. 3,129,753. As is clearly indicated in that patent, the cabinet depth must be maintained at a certainl minimum `level in order to accommodate the relatively large discharge scroll peculiar to centrifugal fans.

With the aforesaid cabinet size considerations in mind,

the primary object of my invention is to provide a fancoil unit of smaller .depth than units of comparable capacity now available.

The salient feature of my invention which permits me to accomplish this objective is a unique arrangement of a plurality of small axial llow fans within a fan-coil housing. I

My invention is particularly characterized by the mounting of spaced apart axial llow fans on a common drive shaft extending longitudinally of a rectangular fancoil cabinet having inlet openings in one wall and outlet openings in a second wall extending parallel to said drive shaft, the air discharging from said fans being diverted towards said outlet openings by a plurality of baille means extending across the discharge path of each of said fans.

My improved fan-coil unit has as a further distinctive feature thereof a unitary fan housing-air diverter member mounted longitudinally within a casing and having spaced apart sections with concentric openings therein in which axial ow fans are positioned and a plurality of air diverting portions disposed opposite each of said openings, said air diverting portions being inclined towards outlet openings in the casing.

Still another feature of my invention is the utilization of sound absorbing material on the above mentioned baille ICC or air diverting portions so as to dampen the noise generated by axial llow fans. n

These and other features and advantages of my invention will become readily apparent as the following description is read in conjunction with the accompanying drawings, of which:

FIGURE 1 is an exploded, perspective view of a preferred form of the fan-coil unit of my invention;

FIGURE 2 is a vertical section view taken along line 2 2 of FIGURE 1;

FIGURE 3 is -an exploded, perspective view of an alternative form of the fan-coil unit of my invention; and

FIGURE 4 is a vertical section view taken along line 4 4 of FIGURE 3.

With reference to FIGURES 1 and 2, my improved air conditioning unit comprises a rectangular cabinet 1 provided with a return air inlet grille 2 in the lower part of front wall 4 and an air outlet grille 6 in top wall 8, and a heat exchange coil 10 of the conventional finned tube construction supported within cabinet 1 between vertical partitions 11 and 12. An additional inlet 5 in the lower part of back wall 14 communicating with the outside atmosphere permits the unit to circulate fresh air. End pockets 9 are formed between partitions 11, 12 and end walls 16. Fan drive motor 18 is housed within left end pocket 9 and has its output shaft passing inwardly through partition 11 to a point of connection with flexible coupling 20. A drive shaft 22 extends longitudinally within cabinet 1 in a direction parallel to outlet grille 6, and is connected at one end to the other side of coupling 20. The other end of drive shaft 22 is rotatably supported within bearing 24 mounted on partition 12.

A plurality of spaced apart, axial llow fans 26 are mounted on drive shaft 22 in the manner shown. Coupling 2i) is preferably of the angularly flexible type so as to be able to accommodate any angular displacement of relatively long drive shaft 22. The rotation of drive shaft 22 by the operation of motor 18 will cause air to discharge from fans 26 in a path generally parallel to heat exchange coil 10 and outlet grille 6. In order to turn the air so that it -will ilow over coil 10 and outwardly through discharge grille 6, I provide a plurality of baille elements 28 positioned across the air discharge path of each fan 26. Batlle elements 28 form a portion of a continuous, unitary member generally indicated -by numeral 30, which also serves as a housing for fans 26. Member 30 and the fanshaft assembly are shown removed from cabinet 1 in an exploded view in FIGURE 1 for purposes of clarity. Member 30 includes a plurality of substantially vertically oriented sections 32 having fan openings 34 therein. Batlle elements 28 are interconnected by vertical sections 32. Member 30 may be formed into the undulating shape shown from a single piece of sheet metal. Drive shaft 22 is passed through openings 34, and holes 19 in baille elements 28, with one fan 26 being mounted at a time on shaft 22 as it is guided through the entire length of member 30. The hubs 23 of fans 26 are secured to shaft 22 by means of set screws 25 or the like. Each fan 26 is positioned within one of the openings 34 in sections 32. The entire assembly consisting of member 30, drive shaft 22 and fans 26 is then positioned within casing 1. Member 30 is secured in place by fastening flanges 35 and 36 at its opposite ends to vertical partitions 11 and 12 with sheet metal screws 37.

An air lter 38 is located across the bottom of the unit above air inlet openings 2 and 5. Dampers 40 and 41 control the llow of air into the unit through fresh air and return air inlet grilles 5 and 2 respectively.

In the embodiment of FIGURE l, baille elements 28 are shown inclined throughout their length. Baflles of other shapes may be employed satisfactorily, just so long as there is a baffle exit portion extending towards outlet grille 6. The inclined -bafe arrangement shown is preferred, as opposed to vertically positioned bafiies, because of the minimum static pressure loadA which it imposes upon fans 26. Stationary turning vanes could also be employed in the discharge path of fans 26 between vertical sections 32 and baies 28 in order to assist in turning the air in a radial direction.

In order to prevent the transmission of noise generated by axial flow fans 26, fibrous sound attenuating material 42 is bonded to batlie elements 28. Additional sound dampening material may be employed as desired in order to minimize sound transmission,

The unit shown in FIGURES l and 2 is adapted for heating or cooling operation. Thus a drain pan 13 is fastened under heat exchange coil in order to catch the condensate which forms when the air is being cooled. Capacity control is achieved by means of face and bypass damper 44 which may be pivoted from the position shown providing full air ow over heat exchange coil 10 through intermediate settings to a position against the face of coil 10. In the latter position, all of the air would bypass coil 10. Also, insulating material 3 is provided on the interior walls of the unit in order to prevent condensation on the .outside of cabinet 1 when a cooling fiuid is being circulated through heat exchange coil 10,

During operation, motor 18 is energized and a hot or cold uid is circulated through heat exchange coil 10. As is indicated by the ow arrows in FIGURES l and 2, the operation of fans 26 will cause air to flow upwardly through inlet .openings 2 and 5 and over filter 38 into the inlet chamber for each fan formed under baffle elements 28. Each fan will discharge an air stream in an axial direction against its respective opposed bafiie element 28. The multiplicity of air streams will thus be diverted upwardly so as to provide air flow across substantially the entire length of heat exchange coil 10 and out discharge grille 6. Fans 26 have been shown as the propeller type for exemplary purposes only. Fans of the vane-axial type, which would also produce fiow in an axial direction, could also be employed.

FIGURES 3 and 4 illustrate a variation of my improved fan-coil unit wherein heat exchange coil 10 is placed near the bottom of the unit under fans 26, as opposed to the top coil placement shown in FIGURES l and 2. Like reference numerals are used to identify the same parts illustrated in FIGURES l and 2. The unit of FIGURES 3 and 4 is adapted for heating and Ventilating only. Thus the drain pan under the coil and the insulation on the casing have been omitted. Gasket material 46, 47 is used to form a seal between heat exchange coil 12 and the opposed walls 4 and 14 of casing 1. Somewhat better airl distribution across heat exchange coil 10 can be obtained by placing the coil under the fans 26 in the manner shown in FIGURES 3 and 4. With this arrangement the fans tend to draw air across the entire surface of the coil. The possible disadvantage with the top coil positioning of FIG- URES 1 and 2 is that dead spots of limited air fiow may exist in the portions of the coil directly above fans 26.

`11;.1" Y These sections of vthecoil would be somewhat' shielded from air flow on such a blow-through design byhe p01'- tions of member 30 forming a housing over the top of fans 26. f

By the employment of a plurality of axial flow fans in combination with the unique unitary fan housing-air diverting member 30 inthe manner shown,f.I,have been able to realize a substantial reduction -in fan coil unit depth in comparison with the-conventional designs which incorporate centrifugal fans. i v y i I do not intend ,that my invention should vbe limited to the particular embodimentsshown, which are illustrative only. For example, a multi-.stage axial low fan arrangement could be employed in place of the single stage fans 26 shown. Such a design would'comprise a number of sets of closely spaced staged fans withstraightening vanes in-between the first and second stages. A plurality of such fan assemblies would be positioned along shaft^22 in spaced relation, with baffle elements 28 being disposed across the discharge path of the second or final stage Yof each fan set. The purpose of multi-stage fan Iassemblies would be to develop greater static pressures. It is anticipated that various other modifications of my improved fan-coil unit will occur to those skilled in the art, which will be within the scope-0f my invention as defined by the following claims.

I claim:

1. A heat exchange unit comprising: a rectangular casing having air outlet openings in one wall thereof and air inlet openings in another wall; a heat exchange coil located within said casing between' said inlet and outlet openings; a unitary fan housing-air diverting member disposed substantially longitudinally -within said casing; said member comprising a plurality of spaced apart sections with apertures therein and a plurality of air diverting portions disposed opposite each of said apertures and extending towards said outlet openings; a drive shaft extending within said casing through said member; power means for actuating said drive shaft; and a plurality of axial flow fans mounted on said drive shaft within said apertures.

2. A heat exchange unit as defined in claim 1 wherein said air diverting portions are inclined at an angle to the vertical.

3. A heat exchange unit as defined in claim 1 wherein said sections with apertures therein are disposed in planes substantially normal to said one wall.

References Cited UNITED STATES PATENTS 1,889,588 11/1932 Anderson 16s-122x 1,903,143 3/1933 shurueff 16s-54x FOREIGN PATENTS i 281,700 12/1964 Netherlands.

ROBERT A. OLEARY, Primary Examiner.

T. W. STREULE, Assistant Examiner. 

